GLP-1 drugs linked to 11-fold higher regurgitation rate under anesthesia

by AAGBI

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New research presented at the Association of Anaesthetists Annual Meeting in Liverpool, UK (Sept. 16–18), and published in the journal Anaesthesia, shows that among patients undergoing surgical procedures under the care of an anesthetist, the rate of a complication known as regurgitation is 11 times higher among patients taking the new class of diabetes and obesity medications glucagon-like peptide-1 receptor agonists (GLP-1 RAs) than among patients not taking those drugs—although the absolute risk of this complication remains small.

The study is led by Dr. Kariem El-Boghdadly of Guy's and St Thomas' NHS Foundation Trust and King's College London, UK, and colleagues on behalf of the GLIMPSE Resident Research Networks and Collaborators.

The use of GLP-1 RA drugs, including semaglutide (trade names Ozempic and Wegovy) and tirzepatide (Mounjaro), has boomed across the UK and other developed nations in the past few years, first for treatment of type 2 diabetes and then for obesity, or both.

Many patients (more than 40% in this study) obtain their prescriptions through online pharmacies, unlike other drugs that are most often obtained through general practitioners (GPs) or hospital prescriptions.

Patients and the general public across the UK are broadly familiar with instructions not to eat or drink for certain periods before operations involving anesthesia. However, one effect of GLP-1 RA drugs is delayed gastric emptying, or slowing the rate at which food and fluid leave the stomach. Thus, patients treated with these drugs before their operations may not have empty stomachs during the procedure.

This, in turn, can increase the risk of regurgitation of stomach contents, which could potentially enter the lungs, known as pulmonary aspiration.

It is unclear what proportion of patients receiving anesthetic care are taking GLP-1 RAs, what strategies are used in their perioperative management and whether the incidence of regurgitation and pulmonary aspiration is greater in this population.

Anesthesia study across the UK

The team performed a nationwide study of adults undergoing elective or emergency procedures under the care of an anesthetist. Patients were screened for GLP-1 RA use in the three months before the index procedure. Routine data were collected on patients, procedures, anesthesia and outcomes, including pulmonary aspiration and regurgitation.

The primary outcome was the proportion of patients receiving GLP-1 RAs. Secondary outcomes described the preoperative management of GLP-1 RAs; anesthesia and airway management in patients receiving GLP-1 RAs; and the incidence of regurgitation and pulmonary aspiration.

Higher complication rates

Of 47,039 patients from 119 sites across the UK, 1,348 (2.9%) reported receiving GLP-1 RAs. Perioperative management varied regarding drug cessation, anesthesia and airway management. The incidence of pulmonary aspiration and/or regurgitation in the non-GLP-1 RA cohort was 57/45,691 (0.12%); in the GLP-1 RA cohort, it was 19/1,348 (1.41%) (with 17 regurgitations and two aspirations), meaning those receiving GLP-1 RAs were 11 times as likely to experience these complications in this study.

Overall, 1 in 36 patients undergoing anesthesia were receiving GLP-1 RAs. Of these, more than 40% obtained the medication through sources other than GP or specialist prescriptions, with the most common indication being weight management. The incidence of pulmonary aspiration and/or regurgitation in people receiving GLP-1 RAs was 1 in 71, most commonly reported during awakening from anesthesia (53% during awakening, compared with 13% at the beginning of anesthesia and 13% during surgery).

Conflicting medication guidance

The results show wide variation in practice regarding the perioperative cessation of GLP-1 RAs. Nearly a third of patients had been advised to hold their GLP-1 medication preoperatively, with most medications omitted for 8–14 days, consistent with a request to stop the drug for one week.

This observed practice contrasts with national guidance from the Association of Anaesthetists, which recommends continuing GLP-1 RAs throughout the perioperative period, as stopping the medicines for less than 3–4 weeks might not be long enough for the effect on the stomach to wear off.

Since tirzepatide and semaglutide have elimination half-lives of five and seven days, respectively, not taking these drugs for 25 and 35 days (five half-lives) would be required to effectively eliminate them from the body. It is unclear, however, how long these medications need to be held preoperatively to reduce the risk of residual gastric contents.

The 7th National Audit Project (NAP7) activity survey analysis of serious complications around anesthesia (a national UK data collection study for anesthesia) combined pulmonary aspiration and regurgitation events and reported a rate of approximately 1 in 660. In this new study, the rate of aspiration and/or regurgitation events in patients not receiving GLP-1 RAs was 1 in 802 (57 of 45,691), which is consistent with NAP7 data.

Conversely, patients receiving GLP-1 RAs had an event rate of approximately 1 in 71 (19 of 1,348). These differences appear to be clinically relevant and contrast with other published data.

Limits on causal conclusions

The authors highlight that these complications in people taking GLP-1 RAs occurred despite clinicians tending to select airway management options that may mitigate the risks of pulmonary aspiration and regurgitation.

They say, "However, although our results suggest that GLP-1 RAs are associated with an 11-fold increase in the incidence of pulmonary aspiration or regurgitation, causality cannot be determined, and this association may be due to unmeasured confounding. For example, obesity and diabetes are known risk factors for pulmonary aspiration, and people with obesity and diabetes are overrepresented among those receiving GLP-1 RAs in our cohort. Furthermore, our data may underestimate the incidence of pulmonary aspiration and regurgitation in patients who were not receiving GLP-1 RAs."

Potential limitations of the study include its use of anesthetists not directly involved in the research, including those screening for GLP-1 RA use in preoperative assessments, who may not have included the information, or patients who may not have disclosed it. Clinicians may also have been reluctant to report all aspiration and regurgitation events.

The authors conclude, "1 in 36 patients undergoing anesthesia care receive GLP-1 RAs and their perioperative management is variable. A range of airway management techniques consistent with reducing aspiration risk were observed, and despite this, the incidence of pulmonary aspiration and/or regurgitation was 1 in 71 in patients receiving GLP-1 RAs; this occurred most commonly as patients woke up from anesthesia.

"These data are not generalizable, but highlight the importance of patients taking GLP-1 RAs informing their anesthetists about this, regardless of where they get them."

They add, "As for any medication, it is important for patients to disclose that they are using GLP-1 RAs before any procedure requiring anesthesia, regardless of the source of the medicines. As use of GLP-1 RAs is increasing, it remains good practice for anesthetists to consider specifically asking patients if they are taking these medications before anesthesia."

Publication details

Peri-operative glucagon-like peptide-1 receptor agonist use and outcomes: a national prospective multicentre cohort study, Anaesthesia (2026).

Journal information: Anaesthesia

Key medical concepts

Glucagon-Like Peptide-1 Receptor AgonistsDelayed gastric emptying

Clinical categories

Anesthesiology Provided by AAGBI Who's behind this story?

Swati Mestri

Swati Mestri holds a bachelor's degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space. Full profile →

Robert Egan

Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language. Full profile →

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